A roller cutter is a cutting tool that revolves freely around a shaft attached to the cutting head of a tunnel boring machine.
During rotation of the head and under the influence of thrust, the roller cutter rolls over the cutting face and chips out the rock in the form of scale-like plates.
Thus the cutting head includes a plurality of roller cutters evenly distributed over its surface.
Conventionally, the roller cutters are mounted within a housing on the cutting head by means of bolts.
The problem of changing the roller cutters occurs particularly in the case of a confined face tunnel boring machine, because access to the cutting head and to the roller cutter mounting hardware is difficult and the working environment is under hyperbaric conditions.
In such tunnel boring machines, the changing of the cutting head is carried out, for safety reasons, from the rear of the cutting head, that is the side of the cutting head opposite the cutting face.
The procedure for changing a roller cutter often demands the exertion of considerable force (sledgehammer blows for example) for loosening the used roller cutter from its housing, due to jams and the absence of guidance for the roller cutter, which is poorly compatible with work under hyperbaric conditions.
At present, the procedure for changing a roller cutter consists of equipping the roller cutter with lifting eyes, to lift it using a pulley block running along a rail, to load it onto a cart running through the equipment airlock and to bring it back to the rear inside the shield, at atmospheric pressure.
During dismantling, it is also necessary to progressively collect all the elements (wedges, screws, bolts, etc.) necessary for mounting the roller cutter and which will be re-used for mounting the new roller cutter.
Before inserting the new roller cutter into its housing, it must be properly positioned, which requires a painstaking manual intervention.
Once the roller cutter is pushed toward its operating position, several blocking wedges are put in place, which are held by means of bolts.
It will be understood that this procedure is long and tedious for the operators.
One object of the present invention is therefore to implement a method for replacing a roller cutter which makes it possible to reduce, or even to eliminate, any human intervention during the replacement of a roller cutter.
Another object of the invention is to propose a roller cutter which lends itself to such a method.
Another object of the invention is to obtain a roller cutter handling device suited to the implementation of this method, by making it possible in particular to avoid any loss of components.
Likewise, the roller cutter handling device must be easy to clean and not include any areas that retain water or mud.
Finally, this device must be usable in existing cutting heads without requiring modifications to the same.